Tissue- and stage-specific RNA patterns in Drosophila as revealed by gradient formamide gel electrophoresis

The in vitro labeled RNAs in the accessory glands from male adults, and in the salivary glands and fat body from developing larvae of Drosophila melanogaster were separated on linear gradient acrylamide gels in formamide. The patterns appear to be tissue- and stage-specific, and several lines of evidence indicate that the visualized radioactive bands include both hnRNA and messages.     

Tissue- and stage-specific RNA patterns inDrosophila as revealed by gradient formamide gel electrophoresis

Summary The in vitro labeled RNAs in the accessory glands from male adults, and in the salivary glands and fat body from developing larvae ofDrosophila melanogaster were separated on linear gradient acrylamide gels in formamide. The patterns appear to be tissue- and stage-specific, and several lines of evidence indicate that the visualized radioactive bands include both hnRNA and messages.Acknowledgments. The financial support by the Swiss National Science Foundation and the George and Antoine Claraz-Schenkung is gratefully acknowledged. I thank Prof. Max Birnstiel for providing me with the sea urchin histone mRNA and Prof. Martin Billeter for providing me with the rabbit globin mRNA as RNA markers.     

Albumen-gel as a supporting medium in zone electrophoresis

Riassunto Un gel composto dalle numerose frazioni proteiche dell'albumina d'uovo fu preparato ed usato quale mezzo di supporto per la separazione elettroforetica di siero-proteine marcate con¹³¹I.A causa di un notevole flusso elettro-osmotico la separazione proteica, dimostrabile mediante autoradiografia, si spostò verso la regione catodica mostrando tuttavia analogie con quella ottenibile su gel di amido.     

Political forecasting as a management tool

Political forces in developing countries permeate and significantly shape the business environment. Yet the political information used by managers is usually general, subjective and superficial. Managers lack an appropriate analytical framework for systematically examining political factors and forecasting their impact on the firm. This paper attempts to present such a framework. The framework focuses on the impact of political forces on development strategies, public policies and policy instruments. It then discusses how the analysis of these factors can be made managerially relevant by integrating them with firm specific characteristics and corporate strategy. This approach departs from many of the traditional political forecasting techniques which only concentrate on macro-level factors and indicators.     

Density gradient centrifugation of cells separated from multicellular tumor spheroids

Summary Cells from a murine fibrosarcoma (FSa) have been grown in vitro as multicell tumor spheroids (MTS). The growth rate of these MTS was determined. Follwing selected periods of growth, MTS were made into a single cell suspension and separated on linear density gradients of Renografin. While only 1 population of cells was separated from small spheroids (400 m diameter), at least 3 subpopulations of tumor cells were separated and isolated from large spheroids (800 m in diameter).This investigation was supported in part by grants numbered CA-18628 and CA-06294, awarded by the National Cancer Institute, DHEW.     

Two-dimensional electrophoresis of rat serum esterases in cellulose acetate and acrylamide gradient gel

Zusammenfassung Isoenzyme von Serumesterasen wurden zuerst mit Zelluloseazetat und dann mit einem Gradientgel von Polyakrylamid mit zweidimensionaler Elektrophorese bei der Ratte untersucht. Ein neues Band, das eine starke Albuminesteraseaktivität aufweist und unempfindlich gegen 10^–3 M Physostigmin ist, wurde somit gefunden. Von 17 Esterasebändern waren 7 empfindlich auf Physostigmin, und 3 wurden auch durch Iso-OMPA gehemmt, während 284-C-51 gar keinen Effekt zeigte.

---

---

Supported by a grant from the Sigrid Jusélius Foundation, Finland.     

Density gradient centrifugation of cells separated from multicellular tumor spheroids.

Cells from a murine fibrosarcome (FSa) have been grown in vitro as multicell tumor spheroids (MTS). The growth rate of these MTS was determined. Following selected periods of growth, MTS were made into a single cell suspension and separated on linear density gradients of Renografin. While only 1 population of cells were separated from small spheriods (400 mum diameter), at least 3 subpopulations of tumor cells were separated and isolated from large spheroids (800 mum in diameter).     

Isoenzymes of some oxido-reductases in theCandida genus as a basis of species identification after electrophoresis

Zusammenfassung Nach Elektrophorese in Agargel wurden die Isoenzyme von G-6-PDH, LDH und MDH in Extrakten vonCandida albicans, C. tropicalis, C. pseudotropicalis, C. crusei undC. utilis untersucht. Es liessen sich diverse Isoenzyme von unterschiedlichem Aktivitätsgrad und wohl auch verschiedener Lage in den Isozymogrammen nachweisen, was bestimmte Schlüsse auf betreffendeCandida-Arten erlaubt.     

Differential neuronal radiosensitivity as a tool for the study of short connections

Résumé La radiolésion aigue du bulbe olfactif provoque des dommages sélectifs aux petits interneurons. L'examen au microscope électronique du tissu irradié a mis en évidence la présence de nombreuses terminales en dégénérescence, au niveau de la couche plexiforme. Elles ont été interprétées comme étant des dendrites appartenant aux granules radiolésées par leur position post-synaptique dans des synapses réciproques avec des dendrites mitrals. On propose d'utiliser cette méthode pour l'étude des connections interneuronales courtes dans certains endroits du SNC.

---

---

This work was partially supported by grants from the Medica Research Council of Canada and Conseil Medical de la Recherche du Québec.     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.     

Density gradient centrifugation of tumor cells from needle biopsies and their respective source tumors: a comparison of density distributions

Summary A needle biopsy technique was applied to a murine fibrosarcoma (FSa) tumor system. FSa tumors of 8 mm diameter in size were biopsied and then made into single cell suspensions. Resulting density profiles of cells from both sources were compared following centrifugation in Renografin gradients. In all cases, there was excellent agreement between the density profiles of the material from each of the biopsies and the corresponding solid tumors.This investigation was supported by grant CA-18628, awarded by the National Cancer Institute, Department of Health and Human Services.     

Developmental genes as a potential tool in population ecology of complex animal life cycles?

Many aquatic invertebrates possess complex life cycles, which include a switch from a vegetative to a sexual mode of reproduction. While sexual reproduction is usually linked to slow rates of propagation, vegetative reproduction leads to high rates of clonal propagation and a fast increase in population size. I have attempted to identify developmental genes which are differentially expressed between sexually and vegetatively reproducing individuals. Quantitative assays of the expression of those diagnostic genes could be applied to field samples to gain information on the reproductive status of the sample. Here I outline a general strategy for identifying and testing the usefulness of homeobox genes as candidates for regulatory genes whose expression patterns are indicative of a sexual or vegetative developmental phase.     

Directed evolution as a tool for understanding and optimizing nucleic acid polymerase function

Polynucleotide polymerases play a crucial role in transmitting genetic information from generation to generation, and they are the most important reagents in biotechnology. Although classical crystal structure analyses as well as biochemical studies have significantly contributed to our understanding of how DNA polymerases function, surprising new insights regarding the importance of certain residues and protein motifs, or of their mutability have been achieved in recent years by evolutionary approaches. Directed evolution has also facilitated the generation of polymerases with tailored substrate repertoires or with stabilities and activities beyond those of their naturally evolved counterparts. Recent new insights in polymerase structure-function relationships and new achievements in the development of tailored polymerases for current methods of nucleic acid synthesis will be summarized in this article. Received 22 April 2005; received after revision 20 July 2005; accepted 27 July 2005